U.S. patent number 5,747,134 [Application Number 08/703,933] was granted by the patent office on 1998-05-05 for continuous polymer and fabric composite.
This patent grant is currently assigned to Reef Industries, Inc.. Invention is credited to Abdeally Mohammed, Lyndell Kyle Wynne.
United States Patent |
5,747,134 |
Mohammed , et al. |
May 5, 1998 |
Continuous polymer and fabric composite
Abstract
The polymer and fabric composite includes at least two polymer
sheets with fabric attached covering substantially one side of the
polymer sheets. In one embodiment, one of the sheets has a strip of
polymer along at least one edge not backed by the fabric. This edge
forms a lip that can be attached to another polymer sheet to form a
strong bond between the two polymer layers. In another embodiment
multiple polymer sheets are prepared with the fabric backing
covering substantially one side leaving a lip of polymer for
attachment along an edge of each of the polymer sheets. Additional
similarly prepared polymer sheets with a polymer lip and fabric
backing can be attached to manufacture the desired size of
continuous composite.
Inventors: |
Mohammed; Abdeally (Houston,
TX), Wynne; Lyndell Kyle (Kingwood, TX) |
Assignee: |
Reef Industries, Inc. (Houston,
TX)
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Family
ID: |
22740608 |
Appl.
No.: |
08/703,933 |
Filed: |
August 28, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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200166 |
Feb 18, 1994 |
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Current U.S.
Class: |
428/57; 428/192;
428/189; 428/190; 405/151; 428/193 |
Current CPC
Class: |
B09B
1/00 (20130101); B32B 27/12 (20130101); E02D
31/004 (20130101); B29C 66/7292 (20130101); B29C
66/73921 (20130101); B29C 66/723 (20130101); B29C
66/53461 (20130101); B29C 65/02 (20130101); B29C
65/18 (20130101); B29C 66/112 (20130101); B29C
66/1122 (20130101); B29C 66/114 (20130101); B29C
66/1222 (20130101); B29C 66/1224 (20130101); B29C
66/1282 (20130101); B29C 66/12841 (20130101); B29C
66/131 (20130101); B32B 7/12 (20130101); B32B
27/32 (20130101); B29C 66/43 (20130101); B29C
66/723 (20130101); B29C 65/00 (20130101); B29C
66/7394 (20130101); B29L 2009/00 (20130101); B29C
66/7392 (20130101); Y10T 428/19 (20150115); Y10T
428/24777 (20150115); B29C 65/08 (20130101); B29C
66/7234 (20130101); Y10T 428/195 (20150115); Y10T
428/2476 (20150115); Y10T 428/24752 (20150115); Y10T
428/24785 (20150115); B29C 66/71 (20130101); B29C
66/71 (20130101); B29K 2023/00 (20130101); B29C
66/71 (20130101); B29K 2021/00 (20130101) |
Current International
Class: |
B09B
1/00 (20060101); B29C 65/00 (20060101); B32B
27/12 (20060101); D04H 13/00 (20060101); E02D
31/00 (20060101); B32B 007/00 () |
Field of
Search: |
;428/57,189,190,192,193
;405/151,251,262 ;442/263,286,394 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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A1310892 |
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Mar 1992 |
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AU |
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8713653.8 |
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Jan 1987 |
|
DE |
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9400650.4 |
|
Apr 1994 |
|
DE |
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B32B3108 |
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Jun 1990 |
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WO |
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WO90/08035 |
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Jul 1990 |
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WO |
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Other References
Koerner, Robert M., Designing With Geosynthetics, Third Edition,
pp. 58-59, 426-429, 445-448, 578-583, 704-705, 719, 757-761 (1994).
.
Casper, M.S., "Nonwoven Textiles", Noyes Data Corporation, Park
Ridge, New Jersey, 1975, pp. 269-271. .
Giroud, J.P., "Design of Geotextiles Associated with Geomembranes",
Second International Conference on Geotextiles, Las Vegas, U.S.A.,
pp. 37-41. .
Giroud, J.P., "Designing with Geotextiles", pp. 257-272. .
Giroud, J.P., "Geomembrane Protection", pp. 99-104. .
Motan et al., "Geomembrane Protection by Nonwoven Geotextiles",
Geosynthetics '93--Vancouver, Canada, pp. 887-900. .
Paulson et al., "Multiple Geotextile Layers Used for Geomembrane
Support in a Landfill: The Marion County (Florida) Landfill
Project", Geosynthetics '93--Vancouver, Canada, pp. 1287-1300.
.
Polyfelt, "Geotextiles for Waste Containment Systems". .
Polyfelt, "Geomembrane Containments". .
Poly-Flex "Polyethylene Geomembranes for Pollution Abatement and
Water Conservation". .
Wong et al., "HDPE & VLDPE Geomembrane Survivability",
Geosynthetics '98--Vancouver, Canada, pp. 901-914. .
PCT Search Report mailed Jun. 21, 1995. .
Letter from A. Spear in Geotechnical Fabric Report, Mar./Apr. 1990.
.
H.E. Haxo, Jr., et al., "Destructive Testing of Geomembrane Seams:
Shear and Peel Testing of Seam Strength", pp. 89-115 in The Seaming
of Geosynthetics, Edited by R. M. Koerner (1990). .
Peggs et al., "Evaluation of a Friction/Drainage Structured
Geomembrane", pp. 1053-1064, in Geosynthetics '93 Conference
Proceedings--Vancouver, Canada..
|
Primary Examiner: Bell; James J.
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
This application is a file wrapper continuation of U.S. application
Ser. No. 08/200,166, filed Feb. 18, 1994 abandoned.
Claims
We claim:
1. A polymer and fabric composite comprising
a first sheet of polymer;
a fabric layer attached to the first polymer sheet covering
substantially one side of the first polymer sheet leaving at least
one strip along at least one edge of the polymer not backed with
the fabric layer;
the strip along at least one edge of the first polymer sheet
providing at least one lip attachable to another sheet;
a second polymer sheet; and
the first polymer sheet attached by one of said lips to the second
polymer sheet.
2. A polymer and fabric composite of claim 1 additionally
comprising
a fabric layer attached to and at least partially covering one side
of the second polymer sheet; and
the lip of the first polymer sheet attached to the polymer layer of
the second polymer sheet.
3. A polymer and fabric composite of claim 1 additionally
comprising
the second polymer sheet attached to a fabric layer covering
substantially one side of the second polymer sheet leaving at least
one strip of polymer not backed with a fabric layer along at least
one edge of the second sheet; and
one lip of the first polymer sheet attached to the side of the
second polymer sheet on the reverse side of the fabric layer and to
an edge of the second polymer sheet backed with the fabric
layer.
4. A polymer and fabric composite of claim 1 wherein said polymer
sheets are selected from the group consisting essentially of olefin
hydrocarbon based plastics and elastomers; substituted ethylenic
based polymers; heterochain oxygen,, nitrogen and sulfur
substituted polymers; thermosetting resins and mixtures
thereof.
5. A polymer and fabric composite of claim 1 wherein the fabric
layer is selected from the group consisting of synthetic fiber
forming polymers, naturally occurring fibers and mixtures
thereof.
6. A polymer and fabric composite of claim 1 additionally
comprising an additional polymer layer between the polymer sheet
and the fabric layer providing the attachment between the polymer
sheet and the fabric layer.
7. A polymer and fabric composite of claim 1 additionally
comprising a tie layer providing the attachment between the polymer
sheet and the fabric layer selected from the group consisting of
polymer hot melt adhesives and pressure sensitive adhesives.
8. A polymer and fabric composite of claim 1 wherein said polymer
sheets are about 5 to about 100 mil in thickness.
9. A polymer and fabric composite of claim 1 wherein said polymer
layers are attached by heat seaming the lip of the first sheet to
the second sheet.
10. A polymer and fabric composite of claim 1 wherein at least one
of the polymer sheets is a multi-ply laminate comprising two or
more polymer layers.
11. A polymer and fabric composite of claim 1 additionally
comprising a reinforcing scrim.
12. A polymer and fabric composite comprising
a first polymer sheet;
a fabric layer of substantially the same dimension of the first
polymer sheet and attached thereto leaving at least one strip along
an edge of the first polymer sheet with the fabric layer
unattached;
the edge of the first polymer sheet with the unattached fabric
forming a lip for attachment to other sheets;
a second polymer sheet; and
the lip of the first polymer sheet attached to an edge of the
second polymer sheet with the unattached portion fabric layer
placed so as not to interfere with the attachment between the first
and second polymer sheets.
13. A polymer and fabric composite of claim 12 wherein the second
polymer sheet is at least partially covered by a fabric layer.
14. A polymer and fabric composite comprising
a first polymer sheet;
a fabric layer attached to the first polymer sheet covering
substantially one side of the first polymer sheet leaving a strip
of polymer along one edge of the sheet not backed by the fabric
layer;
the strip along the edge of the first polymer sheet providing a
polymer lip attachable to another sheet of polymer;
a second polymer sheet;
a fabric layer attached to the second polymer sheet covering
substantially one side of the second polymer sheet leaving at least
one strip of polymer along at least one edge not backed by the
fabric layer;
the strip along the edge of the second polymer sheet providing a
polymer lip attachable to another sheet of polymer; and
said lip of the first polymer sheet attached to the second polymer
sheet on the side opposite to the fabric layer and to the edge
opposite to the polymer lip of the second polymer sheet.
15. A polymer and fabric composite of claim 14 wherein said polymer
sheets are selected from the group consisting essentially of olefin
hydrocarbon based plastics and elastomers; substituted ethylenic
based polymers; heterochain oxygen, nitrogen and sulfur substituted
polymers; thermosetting resins and mixtures thereof.
16. A polymer and fabric composite of claim 14 wherein the fabric
layer is selected from the group consisting essentially of
synthetic fiber forming polymers, naturally occurring fibers and
mixtures thereof.
17. A polymer and fabric composite of claim 14 additionally
comprising a layer of tie resin between one of the polymer sheets
and one of the fabric layers providing the attachment between the
polymer sheet and the fabric layer.
18. A polymer and fabric composite of claim 14 wherein said polymer
sheets are about 5 to about 100 mil in thickness.
19. A polymer and fabric composite of claim 14 wherein said polymer
layers are attached with by heat seaming the lip of the first sheet
to the second sheet.
20. A polymer and fabric composite of claim 14 wherein at least one
of the polymer sheets is a multi-ply laminate comprising two or
more polymer layers.
21. A polymer and fabric composite of claim 14 additionally
comprising a reinforcing scrim.
22. A polymer and fabric composite comprising
a first polymer sheet;
a first fabric layer attached to the first polymer sheet covering
substantially one side of the first polymer sheet leaving at a
first strip of polymer along one edge not backed by the first
fabric layer;
a second fabric layer attached to the first polymer layer on the
reverse side to the first fabric layer with the second fabric layer
substantially covering the reverse side of the first polymer sheet
leaving a second strip of polymer along the edge of the reverse
side not backed by the second fabric layer said second polymer
strip on an edge other than the first polymer strip;
a second polymer sheet;
a first fabric layer attached to the second polymer sheet covering
substantially one side of the second polymer sheet leaving at a
first strip of polymer along one edge not backed by the first
fabric layer;
a second fabric layer attached to the second polymer layer on the
reverse side to the first fabric layer with the second fabric layer
substantially covering the reverse side of the second polymer sheet
leaving a second strip of polymer along the edge of the reverse
side not backed by the second fabric layer said second polymer
strip on an edge other than the first polymer strip; and
the first polymer sheet attached to the second polymer sheet
whereby said strips of polymer on the first and second polymer
sheets are aligned facing each other and sealed.
23. A polymer and fabric composite of claim 22 wherein the polymer
sheets are selected from the group consisting essentially of olefin
hydrocarbon based plastics and elastomers; substituted ethylenic
based polymers; heterochain oxygen, nitrogen and sulfur substituted
polymers; thermosetting resins and mixtures thereof.
24. A polymer and fabric composite of claim 22 wherein the fabric
layers are a fabric selected from the group consisting essentially
of synthetic fiber forming polymers, naturally occurring fibers and
mixtures thereof.
25. A polymer and fabric composite of claim 22 additionally
comprising a layer of resin between the polymer sheets and the
fabric layers providing the attachment between the polymer sheets
and the fabric layers.
26. A polymer and fabric composite of claim 22 wherein said polymer
sheets are about 5 to about 100 mil in thickness.
27. A polymer and fabric composite of claim 22 wherein at least one
of the polymer sheets is a multi-ply laminate comprising two or
more polymer layers.
28. A polymer and fabric composite of claim 22 additionally
comprising a reinforcing scrim.
29. A geomembrane and geotextile composite comprising
a first sheet of polyolefin geomembrane;
a geotextile layer attached to the first sheet covering
substantially one side of the first sheet leaving a strip along one
edge of the geomembrane not backed by the geotextile layer and the
geotextile substantially flush with the other edges of the first
sheet;
the strip along the edge of the first sheet providing a lip
attachable to another sheet of polyolefin geomembrane;
a second sheet of polyolefin geomembrane;
a geotextile attached to the second sheet covering substantially
one side of the second sheet leaving at a strip along one edge of
geomembrane not backed by the geotextile layer and the geotextile
substantially flush with the other edges of the first sheet;
the strip along the edge of the second sheet providing a lip
attachable to another sheet of polyolefin geomembrane;
said lip of the first sheet of geomembrane attached to the second
sheet of geomembrane on the reverse side to the geotextile layer
and to the edge of the second sheet opposite to the lip of the
second sheet.
30. The geomembrane and geotextile composite of claim 29 wherein
said geomembrane is a polyolefin of sufficient thickness to provide
a strong seal.
31. The geomembrane and geotextile composite of claim 29 wherein
said geomembrane is a polyolefin resistant to chemicals and
significantly impermeable to liquids and gases.
32. The geomembrane and geotextile composite of claim 29 wherein
the lips formed on the polyolefin geomembranes are about one to
three inches wide sufficient to provide an overhang for heat
sealing thereby providing a continuous composite between the first
and second sheets of polyolefin membrane.
33. The geomembrane and geotextile composite of claim 29 wherein
the geotextile is selected from the group of woven and nonwoven
fabrics.
Description
BACKGROUND OF THE INVENTION
Impermeable, strong sheeting used for covers or protective barriers
are necessary in a number of applications. Furthermore, continuous
impermeable coverings for large areas or surfaces are particularly
desirable in environmental, mining, and other projects relating to
outdoor terrain.
Part of the difficulty involved in preparing an impermeable, strong
covering involves the manufacture of a sheeting that can be
augmented during the manufacturing process and further, easily
fabricated to produce a continuous sheet of substantial size. The
large size continuous sheets are desirable for use as barriers of
excavation sites as well as top covers over excavation for
containment. Significant outdoor uses include barriers used with
ponds, land fills, waste disposal and hazardous waste management.
In addition, continuous sheeting is used in mining operation to
prevent leaching of potential dangerous chemicals used in refining.
Other applications are in beachfront protection from oil spills,
waterproof membranes and membrane stabilizers for road
construction.
In these applications it is beneficial to have at least part of the
continuous sheeting in contact with a textile layer. Typically,
lengths of polymer sheets are laid over lengths of textiles. In the
environmental applications the polymer sheets used as part of the
barrier are often called geomembranes while the textile layer is
called a geotextile.
A geomembrane can be plastic or rubber sheeting or reinforced
plastic or rubber sheeting of sufficient thickness or biaxially
oriented plastic sheeting. Geomembranes, depending on the
application, typically range in thickness from 5 mil-100 mil. The
plastic sheeting alone in most instances is either too thin or
sometimes too thick and rigid to provide effective protection
against various mechanical stresses acting on the material.
Problems can also occur from the accumulation of a liquid, such as
ground water, vapor condensation or springs, or gas from organic
degradation or air trapped in the soil underneath the plastic
sheeting, causing it to burst. To prevent damage to the
geomembranes, a geotextile is laid over the substrate or soil and
the geomembrane is laid over the geotextile to protect and
reinforce the geomembrane from damage due to rocks and sharp
objects. The geotextile due to its porosity aids in the efficient
drainage of liquids and gases, preventing costly membrane failure.
The first reported use of such a combined arrangement was in 1971,
although geomembranes and geotextiles reportedly were used
separately starting in the 1940 and 1950's. These systems are now
mandatory by governmental regulations for hazardous and
nonhazardous waste landfills, waste piles, and other environmental
applications. These systems perform better and have replaced the
conventional clay/protective layers.
The geotextiles are made of nonwoven or woven material including
fabrics, synthetic and natural fibers. Nonwoven textiles preferred
for geotextile application are staple needle punched, continuous
needle punched, spunbonded, melt blown, dry laid, wet laid,
spunlaced, spunweb and composite structures. Installation is
normally carried out on site. The ground is sufficiently
conditioned before the installation of the geotextile. First, rolls
of geotextile are laid over the area to be covered. Coverage is
achieved by overlapping the rolls of geotextile with a 1-3 feet
overlap, sewing the rolls together, or bonding with an adhesive at
the site. The geomembrane or plastic sheeting is then rolled over
the geotextile. The plastic sheeting can be sealed by field
fabrication techniques, including extrusion fillet welding,
extrosion flat welding, hot wedge fusion, hot air seaming and
ultrasonic seaming. In these installations most of the work is
carried out at the actual site where working conditions may be
unreliable and further require a significant investment of time and
labor.
The sealing techniques available on site can produce uneven seals
resulting in a defective bond between layers of geomembrane. The
seal may not be good enough to prevent leaks at the seam. Also,
since in many cases the geotextile and geomembrane are simply laid
on top of one another without any joinder between the two layers
slippage can result particularly on a sloped area exposing one of
the layers or ground beneath to moisture, hazardous waste or other
type of leachate. Friction treatment on surfaces of the geomembrane
or geotextile to prevent slippage have been proposed as shown in
U.S. Pat. Nos. 5,056,960 and 5,137,393 issued to Marienfeld on Oct.
15, 1991 and U.S. Pat. No. 5,137,393 Fuhr et al. on Aug. 11, 1992,
respectively.
Hence, an improved system consisting of a fabric and polymer
sheeting, offering the advantages of a simple fabrication
technique, superior performance, ease of installation, versatility
and economics is desirable.
SUMMARY OF THE INVENTION
The new polymer and fabric composite and method for manufacturing
provides a simplified solution to the existing problems of a cost
effective, reliable product for use with small or large areas that
need to be protected from moisture, hazardous waste, runoff or even
solid contamination deposition. A leak proof continuous composite
can be fabricated to specifications covering a surface area of
40,000 ft.sup.2 or more prior to field installation.
The polymer and fabric composite comprises at least two polymer
sheets with fabric attached covering substantially one side of the
polymer sheets. In one embodiment, one of the sheets has a strip of
polymer along at least one edge not backed by the fabric. This edge
forms a lip that can be attached to another polymer sheet to form a
strong bond between the two polymer layers. In the preferred
embodiment multiple polymer sheets are prepared with the fabric
backing covering substantially one side leaving a lip of polymer
for attachment along an edge of each of the polymer sheets. In the
preferred embodiment, the polymer lip of one fabric backed polymer
sheet is attached to an edge of a similarly prepared second sheet
opposite to the polymer lip of the second sheet and attached to the
reverse side to the fabric backing of the second sheet so that the
polymer layers are facing each other. In the preferred embodiment
the polymer layers are heat sealed although any other means of
attachment known to those skilled in the art could be used.
Additional similarly prepared polymer sheets with a polymer lip and
fabric backing can be attached to manufacture the desired size of
continuous composite.
The fabric backed polymer sheets can be made in any configuration
desired for the field application. The lip used for attachment can
be on one or more edges, and one sheet can be attached to several
other sheets. Polymer sheets are typically prepared in rolls. The
fabric backing can be laminated to the back of the polymer roll.
The rolls with lips along one edge can be attached to each other as
described above in seriatim to provide a continuous product
composite with the length and width dimensions as needed. The
continuous composite can be cut at the site to conform with any
curves or angles.
In some cases there may be a need to have a fabric backing on both
sides of the polymer sheet. In an alternative embodiment, the
composite is prepared with a fabric backing covering substantially
one side of the polymer sheet leaving a strip along one edge not
backed by the fabric, and a fabric backing on the reverse side of
the sheet substantially covering the reverse side leaving a strip
of polymer without a fabric backing. A second composite sheet is
prepared in the same manner. In the preferred alternative
embodiment, the first and second polymer sheets are aligned so that
the polymer strips face each other and are sealed to form a
continuous composite.
In another embodiment the fabric backing covers one side of the
polymer sheet but a strip of fabric along one edge is not attached.
When the polymer lip is attached to another sheet, the fabric layer
is placed so it does not interfere with the attachment between the
two polymer sheets. The fabric layer may overlap the fabric backing
of the adjacent sheet.
The polymer used in the invention can be made from any type of
material that can be formed into sheets as described herein. It is
not intended to limit the type of polymer to any material and
polymer sheets can be customized as to materials and thickness as
desired. Polymers with chemical resistant properties may be desired
for certain applications involving hazardous waste and mining
operations. The thickness of the polymer sheet is generally between
about 5 to about 100 mils. Some suggested materials are olefinic
hydrocarbon based plastics and elastomers; substituted ethylenic
based polymers; heterochain oxygen, nitrogen and sulfur substitutes
polymers; thermosetting resins and mixtures of polymers. The
polymer sheets can be made of multi-ply laminates of two or more
layers. The layers may be of the same or different polymers. In
addition, a reinforcing scrim may be included as a layer of the
composite or a layer of a multi-ply polymer sheet.
The fabric can be any suitable type of textile. The fabric may be a
woven or nonwoven textile. The fiber used in the fabric may be one
of many synthetic or naturally occurring fibers or mixtures
thereof.
The continuous composite of the present invention is used in
environmental applications calling for a geomembrane and geotextile
combination. The geomembrane is a polymer sheet that is resistant
to chemicals and significantly impermeable to liquids and gas and
is of sufficient thickness to provide a strong seal when the lips
are overlaid and sealed in attaching one sheet of geomembrane to
another. The geotextile is used as a fabric backing as described
herein and is a woven or nonwoven fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a section through an
excavated containment site.
FIGS. 2 & 2A is a schematic of the continuous polymer and
fabric composite.
FIG. 3 is a schematic of a manufacturing setup to make a preferred
embodiment of the fabric backed polymer sheets.
FIG. 4 is a schematic of the fabric backed polymer sheet with the
polymer lip.
FIG. 5 is a schematic of an alternative embodiment of the polymer
and fabric.
DETAILED DESCRIPTION OF THE INVENTION
There are numerous applications for the continuous polymer and
fabric composite as described in the background of the present
invention and known to those skilled in the art. FIG. 1 shows a
field application for a containment area. The continuous composite
is manufactured at the factory and transported to the site for
installation. Containment area 7 such as a landfill is lined by
continuous composite 8. As shown in FIG. 1 there may be a cover 9
made of the continuous composite over the containment area.
In FIG. 2 is an example of the fabricated composite. The fabric
backed polymer sheet 10 is composed of a polymer sheet 11 and
fabric layer 13. The main components of the composite are the
polymer and fabric. The polymer sheet is of sufficient thickness to
provide the properties desired for the application such as liquid
and gas impermeability, chemical resistance, puncture resistance
and other strength properties. The polymer must also have the
characteristics needed for attachment to other polymer layers to
provide a strong seal.
A number of polymers can be used in the manufacture of the
composite. The following general categories of olefin hydrocarbon
based polymers can be used including polyethylene, polypropylene,
higher olefin based polymers, copolymers of olefins substituted
with ethylene, propylene, butene, and higher olefins, copolymers
with vinyl esters and acrylic based materials, copolymers with
carboxyl containing monomers, natural rubber and polyisoprene,
butadiene rubber, copolymers of butadiene with polystyrene and
polyacrylonitrile, butyl rubber, chlorobutyl rubber,
chlorosulfonated polyethylene rubber. Also, substituted ethylenic
polymers can be used including polystyrene, copolymers with
polybutadiene, acrylonitrile and methyl methacrylate, rubber
modified polystyrene, acrylic polymers, polyvinyl esters, derived
polyvinyl esters, chlorine substituted ethylene, copolymers of
vinyl chlorides with vinyl esters, fluorine and fluorochlorine
containing polymers. In addition, heterochain thermoplastics can be
used including polyamides and polypeptides, polyesters, polyethers,
polyurethanes, polycarbonates, polysulfide polymers, cellulose
derivative polymers, polyimides, polyphenylene oxide, polyarylate
and ketones. Thermosetting polymers including phenol-aldehyde
condensation products, urea-formaldehyde and melamine formaldehyde
products, unsaturated polyester resins, epoxy resins,
polyurethanes, silicones, alkyd polymers, allyl polymers, and
diallyl phthalate polymers can be used. It is not intended to limit
the use of any type of polymer that has the characteristics
described generally herein. Also, mixtures of different polymers
can be used.
Additives to enhance the properties of the polymer sheet or plies
of a multiply laminate polymer sheet may be used. Additives known
to those skilled in the art include fire and flame retardants,
colorants and pigments, ultraviolet absorbers and stabilizers,
biocides, fillers, extenders, anti-oxidants, vulcanizer and impact
modifiers. The polymer membrane can range in thickness from about 5
to about 100 mil, depending on the application.
The fabric can be a textile made from synthetic fiber forming
polymers, naturally occurring fibers and mixtures thereof.
Synthetic fibers can be made from the group consisting of
polyolefins and copolymers, polyvinyls, polyesters, polyamides,
polurethanes, polyacrylonitrile, polyvinyl alcohol, and viscose
rayon. Natural fibers used for fabrics can include jute, hemp,
cotton and wool. These fibers can be used in physically mixed or
constituent mixed systems. Examples of woven materials include a
scrim made from polyethylene, polypropylene, nylon or polyester.
The nonwoven materials may comprise, for example, fibers of
polyethylene, polypropylene and polyethylene terepthalate and other
fiber forming polymers either continuous spun bond or needled
punched. Fiber properties can be enhanced using additives known to
those in the art including fire retardants, colorants, ultra violet
absorbers and stabilizers and antioxidants. Geotextiles used for
composite applications are known to those skilled in the art. The
invention is not intended to be limited to any type of fabric.
FIG. 2 is a cross-section through several fabric backed polymer
sheets attached according to the method of this invention. As an
example shown in one of the sheets the fabric layer 13 is firmly
attached to polymer sheet 11 providing a strong bond between the
polymer and fabric backing. Fabric layer 13 covers substantially
one side of polymer sheet 11 leaving a strip of polymer along one
edge not backed by the fabric. The strip provides a polymer lip 12
on polymer sheet 11 which is used to attach to another fabric
backed polymer sheet 14. Polymer sheet 14 is constructed in a
similar fashion to polymer sheet 10 and has a polymer sheet 16 and
fabric backing 18 and a polymer lip 19 for attachment to adjacent
sheet 20. Sheets can be attached to adjacent sheets in a similar
manner providing a continuous composite.
FIG. 2a is an enlargement of the point of attachment between fabric
backed polymer sheet 10 and the adjacent fabric backed polymer
sheet 14. Lip 12 overlaps the edge of polymer sheet 16 on the
reverse side of fabric 18. Polymer sheets 11 and 16 are attached at
seal 17. The fabricated seal 17 is uniform, continuous, impermeable
with strength equal to roughly the strength of the plastic
sheeting. The multiple sheets 10, 14, 20 and 22 are attached to
each other to form a large continuous composite sheet. Additional
sheets may be used as desired.
The following steps are a preferred method to obtain the continuous
composite of this invention. FIG. 3 depicts a lamination setup. The
polymer sheeting 40 and fabric 42 are laminated together using a
high temperature coat of a suitable tie layer resin 44, which is
pumped through a polymer die 46. The typical properties of a tie
layer material are good adhesion to substrates, good temperature
resistance and good flow properties. The typical temperature of
this coat normally ranges from 530.degree.-630.degree. F. More
typically the temperature ranges from 550.degree.-600.degree. F.
The polymer type for tie layer resin 44 may differ, depending upon
the type of properties desired. Specific grades in polyethylene and
co-polymers, polypropylene and co-polymers can be used as a resin
for attaching the polymer sheet and fabric together. The
polyethylenes can be a low density polyethylene or a linear low
density or a high density polyethylene or mixtures thereof. The
polypropylenes used normally are co or ter polymers of
polypropylene with ethylene or olefin monomers. An acrylic polymer,
for example, an alkyl acrylate such as an ethyl or methyl acrylate
comprising between 10-30% acrylate monomer can be used. A vinyl
acetate co-polymer especially ethylene vinyl acetate comprising
between 10-30% of vinyl acetate monomer may be used. The tie layer
resins can also be used in mixtures with each other operating
temperatures can be lowered when using acrylate and acetate
co-polymers. The width of the composite 48 depends on the
capabilities of the raw material and the equipment. The equipment
typically used has a width from 50 to 150 inches. The rolls 50 and
52 pressure the polymer sheet 40 and fabric 42 together with tie
layer resin 44 to achieve a good level of adhesion of the polymer
sheeting to the fabric. Similar laminations can be achieved by
using a hot melt adhesive or pressure sensitive adhesive as a tie
layer. Hot melt adhesives include low melting polymers including
rubbers, polyolefins, acrylic and acetate co-polymers. Pressure
sensitive adhesives are typically dispersions of rubbers, acrylics
and acetates in water or solvent. Application techniques can be
similar to the methods described herein or could be achieved by
coating rolls as known to those skilled in the art. The lip
overhang 58 is obtained by accurately calculating the spacing of an
index guide on the primary unwind 54, which carries the fabric,
relative to the polymer sheet which is kept stationary on the
secondary unwind 56. The same adjustments could be done with the
polymer sheeting on the primary unwind 54 and the fabric on the
secondary unwind 56.
FIG. 4 shows the preferred embodiment laminate 60 with the fabric
backing 62 attached with tie resin layer 68 to the polymer sheeting
64 with the polymer lip overhang 66. The width of the plastic lip
66 usually ranges from about 1-3 inches, with preferably a lip of 2
inches in the composite product. A lip of more than 3 inches can be
inefficient and not necessary in forming a strong attachment with
respect to material usage. The thickness of the polymer sheeting 64
is important in the design of the product. Typical polymer sheeting
can vary from about 5 to about 100 mil. A sufficient thickness of
the polymer sheeting 64 is necessary to provide a heat seal strong
sufficient to withstand the weight of the material in addition to
the other forces encountered during usage. The amount of tie resin
68 used to attach the fabric 62 and the polymer sheeting 64
together is important to obtain a significant level of adhesion
between the two layers to form a strong composite.
FIG. 5 shows an alternative embodiment with fabric backing on both
sides of the polymer sheet which can also be manufactured using the
lip overhang technique discussed above. Each separate sheet
consists of a polymer sheet and two fabric layers.
FIG. 5 shows 3 sheets that have been attached to form a continuous
composite. Polymer sheet 70 has one fabric layer 72 covering
substantially one side of the polymer sheet leaving a strip 76 of
polymer along the edge not backed by the fabric. A second fabric
layer 74 is attached to the polymer sheet on the reverse side to
the first fabric layer 72 substantially covering the reverse side
leaving a strip 78 along the edge not backed by the second fabric
layer. This construction forms double fabric backed polymer sheet
80 that has two strips of polymer 76 and 78 backed on one side with
fabric. Double fabric backed polymer sheets 82 and 84 are similarly
constructed. The double fabric backed sheets are attached by
aligning the polymer strips on separate sheets facing each other
and sealing.
Both strips 76 and 78 are shown in FIG. 5 facing similar strips on
sheets 82 and 84 to form a continuous composite with fabric on both
sides. This is a high performance composite and can find
applications in areas similar to those discussed above, but is
particularly suitable where extremely high impact and puncture
resistance is required. Various other combinations and composites
can be formed using the above invention by those skilled in the
art.
A preferred method for manufacturing the alternative embodiment
shown in FIG. 5 utilizes the lamination set up shown in FIG. 3.
After one fabric layer has been attached preferably with a tie
layer to a polymer sheet leaving a lip for attachment, a second
fabric layer is attached on the reverse side. The second fabric
layer substantially covers the reverse side of the polymer sheet
except for an edge of the polymer sheet. The second fabric layer
can be attached by the method described herein or other methods
known to those skilled in the art. In the alternate embodiment
strips of unbacked polymer are preferably on edges opposite to each
other on the polymer sheet. The strips of polymer are aligned
facing each other and sealed preferably by heat seaming. The double
fabric backed embodiment of this invention can be made with the
preselected number polymer sheets to form a continuous composite of
the desired size. In some cases more than one edge on each side of
the polymer sheet may need to remain unbacked to provide more than
one polymer strip for attachment to additional sheets.
A preferred method of attachment in preparing the continuous
composite is heat seaming. The integrity of the seams made to
create the continuous composite are important to the success of any
geocomposite construction. In the heat seaming process polymer
molecules at the surface of the two polymer sheets being attached
are thoroughly intermixed on a molecular scale. This is achieved by
a proper combination of temperature, pressure dwell time and
cooling during which there is an interdiffusion of the mobile
molecules on both sides of the interface. A major consideration in
the design of the lip technique for the use in composite systems is
that the design function of the composite is transferred through
the seam. The design function includes impermeability,
transmissivity or of liquids or gases, bedding or cushioning,
hydraulic barriers and load transfer.
A preferred heat seaming technique for the composite is by
electrical resistance heating using a heating bar, which can vary
from 1-50 ft in length. The two ends of the composite are coupled
to each other as described earlier and the heating bar
automatically lowered to achieve a heat seal. The material is held
together under pressure on the heat bar and the dwell time
controlled accurately to obtain a strong impermeable seal. In the
case of the fabric on both sides of the sheet, the heat is
transmitted through the fabric to seal the two polymer sheets. The
choice of fabric is very important while using such a seal. A low
melting fabric will destroy the functionality of the composite as
compared to a high melting fabric such as a nylon or a polyester.
Also, the amount of heat supplied in the double fabric layered
composite is much high than that for the single layered composite.
The seaming can be done continuously in the factory and sheets
connected together to form a continuous composite of 40,000
ft.sup.2 or more in area.
The above developed factory sealing technique has substantial
advantages over the field installed seams. Manufacturing under
pre-established conditions results in a better control of the
quality and aesthetics of the panel. Large panels can be made with
complete uniformity over the whole area of the panel. The rate of
production is much faster due to factory automation at all steps of
handling and seaming also resulting in long consistent runs.
Ambient temperature control in the factory, uniform packaging,
controlled sheet alignment are among the other advantages. The
advantages over the field seaming techniques include--no ambient
temperature variation from day to day--job to job, the amount of
wind on field installation is not a factor, the skill of the
seaming crew critical in field seaming operations is not important,
proper preparation and cleaning of composite surfaces in
nonexistent because of the clean factory environment.
The following examples are provided to illustrate in detail the
materials, methods and techniques of this invention. A brief
description on the examples are given below.
Example 1 is relatively light geomembrane laminated to a relatively
light polypropylene nonwoven geotextile. The increase in physical
properties of the composite and the overlap seam were compared.
Example 2 is a relatively heavy geomembrane laminated to a
relatively heavier polyester nonwoven geotextile. The increase in
physical properties of the composite and the overlap seam were
compared.
Example 3 are the results of the various seaming techniques used on
samples from Example 2.
EXAMPLE 1
In this example a light weight nonwoven geotextile about 4.5
oz/yd.sup.2 made from staple polypropylene fibers was laminated to
a relatively light flexible geomembrane. The geomembrane was
Permalon.RTM. X150 a 4.1 oz/yd.sup.2 (nonwoven fabric units used
for convenience of comparison) geomembrane 9 mil thick made from
polyethylene. The index guide for the nonwoven fabric was adjusted
for a lip distance of about 2.5-about 2.0 inch and material checked
for the exact distance. The lamination was done on a extrusion
laminator. The temperatures in the extruder and die were maintained
at 310.degree. C. and rpm of the screw adjusted so that a tie layer
of between 1-3 mil was obtained. The composite was tested for its
physical properties listed in Table 1 below.
TABLE 1 ______________________________________ Light Geomembrane
Light Geomembrane/ Material Property Permalon .RTM. Light
Geotextile (ASTM) X150 Composite
______________________________________ Grab tensile 92/74 124/151
strength @ break (lbf) ASTM D-4632 MD/TD Puncture 20 87 resistance
(lbf) ASTM D-4833 Impact strength 1.0 2.5 (lbm) ASTM D-1709 Mullen
Burst 69 (deform) 265 (psi) ASTM D-3786
______________________________________
The property of the composite approximate that of a 30-40 mil thick
polyethylene membrane. The weight of the composite is 10.24
oz/yd.sup.2 as compared to 30 oz/yd.sup.2 for a 40 mil thick
membrane. This composite was laminated using a hot sealing bar with
the overlapping as discussed above. The heat was applied to seal
the two geomembrane surfaces to each other, and the overlapping is
achieved so that functionally the geotextile is continuous over the
whole width of the seal. The seal for this composite is about 45
lbf in shear tested according to ASTM D-4545. This seal strength is
sufficient for the relatively lower strength applications for the
composition.
EXAMPLE 2
In this example a medium weight nonwoven fabric about 6 oz/yd.sup.2
made from continuous spunbond polyester geotextile was laminated to
a heavier flexible geomembrane. The geomembrane was Permalon.RTM.
X210, a 10 oz/yd.sup.2 (nonwoven fabrics units used for convenience
of comparison), made from polyethylene. As in Example 1 the index
guide was adjusted for a lip distance of between 2.0 and 2.5 inch.
The process conditions were maintained the same as in Example 1.
The composite properties were tested and a comparison is shown
below in Table 2.
TABLE 2 ______________________________________ Geomembrane
Geomembrane/ Material Property Permalon .RTM. Geotextile (ASTM)
X210 Composite ______________________________________ Grab tensile
179/175 346/329 strength @ break (lbf) ASTM D-4632 MD/TD Puncture
42 135 resistance (lbf) ASTM D-4833 Impact strength 3.6 14.0 (lbm)
ASTM D-1709 Mullen Burst (psi) 150 (deform) 392 ASTM D-3786
______________________________________
The properties of the composite approximate that of a 50-60 mil
thick polyethylene membrane. The weight of the composite is 16.6
oz/yd.sup.2 for a similar geomembrane. The composite may be
laminated together to form a continuous sheeting of any given size
as large as 40,000 ft.sup.2. The technique for heat sealing and
concepts are similar to those discussed above. The seal strength of
the composite as tested according to ASTM D-4545 is 96 lbf in
shear. This is an extremely strong seal and is close to the yield
strength of the material.
EXAMPLE 3
This example illustrates the various seaming techniques for the
formation of an uninterrupted composite sheets for ready
installation. Although the techniques discussed in the example are
related to heat sealing or heat seaming techniques, there are other
alternatives. Various other techniques including ultrasonic
seaming, factory solvent seaming, electrical conduction seaming,
electro magnetic induction seaming that can also be used to
practice this invention.
The most common heat sealing technique is the electrical resistance
heating of an iron bar which is applied on the polymer or the
polymer moved along the bar to give the appropriate adhesion and
sealing strength. The voltage applied can be varied from 0-480
volts, the voltage normally used is in the range of 275-300 V. The
amperage is normally between 150-170 amps. The time of heat sealing
for an appropriate voltage is an important variable when heat
sealing different materials. The rate of cooling is important for
proper recrystallization of the polymer and also to prevent the
material from sticking. A 30 sec cool at 55.degree. F. is normally
sufficient to achieve proper recrystallization. The seaming is
normally carried out with the heat on the geomembrane side, however
a higher voltage can be used to seam through the continuous needle
punched polyester geotextile. The Table 3 below shows the seam
strengths on the composite materials described in Example 2
obtained through various heat seaming techniques.
TABLE 3 ______________________________________ Seam Shear Method
Strength Conditions ______________________________________ Heat bar
- geomembrane 96 lbf 300 V, 24 sec heat heat Heat bar - geotextile
heat 120 lbf 400V, 26 sec heat Continuous feed - heat bar 87 lbf
440.degree. F., 31.2 ft/min Continuous feet - heat bar 70 lbf
440.degree. F., 32.5 ft/min Hot air welder 97 lbf 1000.degree. F.
______________________________________
The materials described in Examples 1 and 2 can be used to prepare
a geocomposite. However the same or similar materials can be used
to prepare a composition for other applications described herein.
The examples described herein are not intended to limit the scope
of the invention generally disclosed.
* * * * *